Four Seasons Hotels and Resorts do not have a loyalty programme like Hilton Hhonors or Starwood Preferred Guest. They do have, AFAIK, a frequent guest program which is by invitation-only, where, supposedly, ALL of a guests preferences, which have been recorded by a Guest Historian, are conveyed to the hotel(s) concerned. The guest is also on a priority list for any upgrades; though it does not guarantee rate breaks or upgrades. According to Wolf Hengst, frequent guests are to receive special promotions from time to time, which are only available to frequent guests. However, it should be noted that in order for Four Seasons to know who are frequent guests, the guest must identify themselves as a frequent guest through a unique ID. This, apparently, is done to ensure the privacy of the frequent guest.

I received such an invitation this past summer from Four Seasons and the information here is based upon the information I have received.

I have also seen elsewhere that each individual FS hotel have their own frequent guest loyalty schemes. While I cannot remember exactly where I read this but the Ritz-Carlton Chicago, A Four Seasons Hotel, as one hotel which have such a programme.